So, as the title says I'm looking to upgrade my GPU. currently I have a gtx 570 on a 1920x1080 res. I'm looking at a gtx 680 for £200 but saw a gtx 770 for £195 however there is an offer on for a gtx 780 for £200 at the moment and planning on getting this over my current gtx 570. what do you guys think?

The GTX 770 has really fallen since Maxwell has come out. How much does a 970 cost? I've seen a few used ones on eBay already, so I am curious what they are going for. A GTX 770 will be a huge upgrade over a GTX 570 in all aspects GPU related.